Brenner tumors are a distinct type of growth that originates in the ovary. These tumors are an uncommon subtype within the broader category of surface epithelial-stromal ovarian neoplasms. While they are generally non-cancerous, there are less common forms that can be borderline or malignant.
Understanding Brenner Tumors
Brenner tumors are a rare form of ovarian tumor, accounting for a small percentage, typically 1-5%, of all ovarian epithelial tumors. The World Health Organization (WHO) classifies them into benign, borderline (also known as proliferative), and malignant variants. Most Brenner tumors are benign, with malignant forms accounting for less than 5% of cases.
These tumors are characterized by nests of transitional epithelial cells, which are similar to the cells lining the urinary tract, embedded within a dense fibrous tissue. Benign Brenner tumors are usually small (2 to 8 centimeters in diameter) and are typically solid with a firm, rubbery consistency. Borderline and malignant Brenner tumors tend to be larger, sometimes reaching 30 centimeters. They can be found at any age, but benign forms are most frequently diagnosed in women 30-70, while borderline and malignant forms usually occur in women 45-65. They are often discovered incidentally during imaging or surgery.
Identifying Symptoms and Diagnosis
Brenner tumors often cause no noticeable symptoms, especially when benign and small. Many are found incidentally during routine pelvic examinations or imaging studies. If symptoms appear, they are usually not specific to Brenner tumors and can include pelvic pain, abdominal pressure, or general abdominal swelling. Larger tumors might lead to a palpable mass in the pelvis or abdomen. Rarely, they can be associated with hormonal activity, potentially causing abnormal uterine bleeding.
Initial evaluation typically involves a physical examination and a pelvic ultrasound to visualize the ovarian mass. Further imaging, such as CT scans or MRI, can provide more detailed information about the tumor’s characteristics, including its solid nature, calcifications, and any cystic components. On CT scans, calcifications are reported in about 85% of Brenner tumors, while MRI often shows low signal intensity on T2-weighted images due to their fibrous content. A definitive diagnosis, including its type (benign, borderline, or malignant), relies on histopathological examination of the tissue after surgical removal. Tumor markers, such as CA-125, are not specific for Brenner tumors and are not used for definitive diagnosis, although abnormal levels can be associated with malignant types.
Treatment Approaches
Surgical removal is the primary treatment for Brenner tumors. The surgical approach depends on the tumor’s size, classification (benign, borderline, or malignant), and the patient’s age or desire for future fertility. For benign Brenner tumors, which are most common, removal of the affected ovary and fallopian tube (unilateral salpingo-oophorectomy) is a frequent procedure. For younger women who wish to preserve fertility, less extensive surgery might be considered if the tumor is small and clearly benign.
For borderline or malignant Brenner tumors, more extensive surgery is typically required for complete removal and staging. This may involve a total abdominal hysterectomy (removal of the uterus) and bilateral salpingo-oophorectomy (removal of both ovaries and fallopian tubes). Lymph node dissection may also be performed to check for spread, although lymphatic spread is less common.
Adjuvant therapies, such as chemotherapy or radiation, are rarely used for benign or borderline cases. For malignant Brenner tumors, platinum-based chemotherapy regimens, often carboplatin and paclitaxel, may be considered after surgery, similar to other epithelial ovarian cancers. The role and regimen for adjuvant chemo-radiation therapy for malignant Brenner tumors are not standardized due to their rarity.
Prognosis and Follow-Up Care
The prognosis for benign Brenner tumors is generally favorable after surgical removal, with recurrence being rare. For borderline and malignant Brenner tumors, the prognosis can vary, but it is often good, particularly when detected and treated early. Malignant Brenner tumors, though rare, can spread within the abdominal cavity or to distant sites like the liver, lungs, or bones.
Due to the rarity of Brenner tumors, a standardized follow-up protocol has not been universally established. Regular follow-up appointments are generally recommended, especially for patients with borderline or malignant tumors. Monitoring may include physical and pelvic examinations, along with imaging studies, to detect any recurrence. For individuals with advanced-stage disease who achieve a complete response, lifelong follow-up may be suggested.